There are numerous known clamping devices that allow an operator to hold and securely restrain a workpiece. One well-known clamping design is a vise clamp having one stationary jaw, and one movable jaw that may be adjusted to clamp the workpiece between the jaws.
Welders and pipe fitters often use a clamp to secure a workpiece such as a length of pipe that must be cut, or welded to another length of pipe. For example, in the construction of a commercial building, there is typically a complex network of piping that must be installed to deliver water to various locations within the building as well as to accommodate the removal of sewage. Successive lengths of pipe are welded to form such pipe networks. Because of the amount of pipe that must be routed through constrained spaces, adjoining pieces of pipe must be precisely aligned prior to welding to ensure that the runs of pipe fit within the constrained spaces set forth in the building design. For most pipe fitting operations, pipe runs are created so that there are primarily horizontal and vertical runs. These runs are interconnected by 90 elbows as necessary to change the direction of the runs.
Because of the weight and size of the sections of pipe to be installed, many of the sections must be assembled at a shop location away from the job site. A job site does not typically have a bench or support that is capable of securing the pipes for assembly. Thus, one continuing problem in pipefitting is the inability for a pipe fitter to assemble sections of pipe at the job site, or to otherwise rework the pipe at the job site.
My earlier U.S. Pat. No. 3,982,739 addressed some of these problems through a portable vise formed by a pair of intersecting plates connected to an orthogonally extending base having a v-shaped cross section. The intersecting plates form two v-shaped spaces and the base forms a third v-shaped space. Clamping flanges may extend from each of the plates as well as from the base. Each clamp member is positionable over its respective v-shaped space to act as a support or frame for a set screw. The set screw is threaded through the clamp and allows a workpiece to be held in the corresponding v-shaped space formed by the intersecting plates or the base.
Another example of a device that is adapted for securing pipe includes the device disclosed in U.S. Pat. No. 5,863,035. This reference discloses a clamping device capable of being mounted to a pipe jack for securing a workpiece, such as a length of pipe. A yoke member is adapted to engage a pipe jack having a v-shaped configuration, and also has a threaded orifice for receiving a threaded stem. A handle attaches to an upper end of the threaded stem. A jaw is attached to the lower end of the threaded stem and is engageable with the workpiece by manipulating the handle to force the jaw against the surface of the workpiece.
U.S. Pat. No. 5,950,998 discloses a portable cable vise especially adapted for securing cable. The vise includes a lower stationary jaw, an upper movable jaw, and means for moving the upper jaw toward and away from the stationary jaw to grip a length of cable between jaw members. The jaws have complimentary shaped recesses for receiving the cable to avoid crushing or damaging the cable. The vise further includes a c-shaped mounting clamp allowing the portable vise to be mounted to a support.
In pipefitting, it is also necessary to cut various lengths of pipes in order to create the pipe network that may be incorporated within a building. Preferably, pipe is cut at the jobsite; however, larger pipe sizes are often cut away from the jobsite because the power saw required to cut the pipe may only be incorporated on a large base or table. Typically, a circular saw, also commonly referred to as a “chop” saw, is used to cut pipe. Examples of references disclosing various types of circular saws include U.S. Pat. Nos. 5,161,443; 5,016,510; and 5,720,096.
While these inventions may be adequate for their intended purposes, none of these inventions incorporate the special features of the present invention as discussed below.